1. Field of the Invention
The present invention relates to a pattern forming method, an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a method for producing an electronic device, and an electronic device. More specifically, the invention relates to a pattern forming method, an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a method for producing an electronic device, and an electronic device, each of which is suitably used in a process for preparing semiconductors such as ICs, a process for preparing liquid crystals or circuit boards such as a thermal head, and lithographic processes in other photo-fabrication. Particularly, the invention relates to a pattern forming method, an actinic ray-sensitive or radiation-sensitive resin composition, a resist film, a method for producing an electronic device, and an electronic device, each of which is suitably used in exposure by an ArF exposure apparatus, an ArF immersion-type projection exposure apparatus, or an EUV exposure apparatus, each using a light source that emits far ultraviolet light at a wavelength of 300 nm or less.
2. Description of the Related Art
Since the development of a resist for a KrF excimer laser (248 nm), a pattern forming method using a chemical amplification has been used so as to compensate for sensitivity reduction caused by light absorption. By way of an example, in a positive chemical amplification method, a photoacid generator included in the exposure apparatus is decomposed by irradiation with light to generate an acid. Further, an alkali-insoluble group contained in a photosensitive composition is converted into an alkali-soluble group by the catalytic action of the generated acid in PEB (Post Exposure Bake) process. Subsequently, development is carried out using, for example, an alkali solution, and thus, the exposure area is removed to obtain a desired pattern.
For the method, various kinds of alkali developers have been proposed. For example, as the alkali developer, water-based alkali developers such as a 2.38%-by-mass aqueous TMAH (tetramethylammonium hydroxide) solution has been widely used.
Due to miniaturization of a semiconductor device, there is a trend toward a shorter wavelength of the exposure light source and a higher numerical aperture (higher NA) of the projection lens and at the present time, an exposure machine using, as its light source, an ArF excimer laser having a wavelength at 193 nm has been developed. A method of filling a high refractive-index liquid (hereinafter sometimes referred to as a “liquid for liquid immersion”) between the projection lens and the sample (that is, a liquid immersion method) has been proposed as a technique for further enhancing the resolution power. In addition, EUV lithography of performing the exposure to ultraviolet light at a shorter wavelength (13.5 nm) has also been proposed.
However, it is actually very difficult to find an appropriate combination of a resist composition, a developer, a rinsing liquid, and the like necessary for forming a pattern with overall good performance, and there is demand for further improvements.
Recently, a pattern forming method using a developer including an organic solvent has been developed (see, for example, JP2008-281975A, JP2010-139996A, JP2010-164958A, JP2009-25707A, and JP1992-39665 (JP-H04-39665A)). For example, in JP2008-281975A, JP2010-139996A, JP2010-164958A, and JP2009-25707A, a pattern forming method including developing a resist composition containing a resin having a repeating unit having a group capable of decomposing by the action of an acid to generate a polar group in a relatively high content using a developer including an organic solvent is described. It is described that by this method, a fine pattern having good line width variation (LWR, LER), exposure latitude (EL), focus latitude (DOF), dimensional uniformity, or the like can be formed.
Furthermore, in JP1992-39665 (JP-H04-39665A), patterning by an organic solvent (xylene) using a resist composition including a copolymer of adamantyl methacrylate and t-butyl methacrylate is described.
In addition, in JP2011-141494A and WO08/149,701, an amine compound having a specific structure inhibiting the diffusion of the generated acids from the viewpoint of improvement of line width variation, or the like, is described.
However, in the phenomenon requiring further fine patterns, for example, in the formation of a fine pattern such as a hole pattern with a pore diameter of 45 nm or less, there has been a demand for further improvement of EL, local pattern dimensional uniformity, and rectangularity and circularity of the cross-sectional shape.